One SSH/SFTP for an addon domain, a different one for the primary domain?

We're thinking about using addon domains for the purpose of creating staging versions of live hosted domains, and just debating the pros and cons amongst ourselves.

One question raised was whether it's possible to have one SSH/SFTP access for the live site, and a different SSH/SFTP access for the addon domain which is sharing the same hosting account. The reason for asking this is because it may be that, from a workflow perspective, we don't want to give permission to the developers working on the staging site to be able to access or upload code on the live site - that'll be taken care of someone else.

Thanks very much for that. One of my devs is advising me of a workaround by using version control (i.e. git). In his own words:

"We can use branches in git (we already to this) and provide 3rd party devs with their own branch of the codebase to work on. This would allow us to separate the live and staging sites. The staging site would automatically deploy code from the 3rd party developer's branch only, while the live site would need an Itomic staff member to make changes to it. You wouldn't be able to accidentally update the live site with the 3rd party branch for example."